Printing press



w. H. SMITH PRINTING PRESS Feb. 27, 1934.

Filed 03%,..13 1931 www retain FRENTING PRESS Waiter lflarold Smith,Toronto, Qntario, Cana-da Application October i3, 1931. Serial No.568,603

(Cl. lill- 4151) 3 Claims.

My invention relates to improvements in printing presses, moreparticularly to the style of press known as a lithographed offset press,which Smploys wo or more cylinders, employing a thin metallic orcelluloid strip for the printing plate and a rubber blanket covering theoffset cylinder to receive the print which in turn contacts With thesheet to be printed being held against the offset cylinder by a thirdcylinder (not shown) which gives the desired impressional contact.

The object of this invention is to provide a cylinder Whosecircumference is exactly equal to the exact length of sheet to beprinted and to provide means for holding the printing plate and therubber blanket securely with a minimum amount of opening for the holdingor clamping means to secure the maxunurn of actual print- 'lng surfacein a srnall ina/chine. This becomes diicult as the diameter is too Smallto allow of any internal clamping devices.

A further object is to allow a number oi narrow plates to be held on thecylinder at the saine time and a single means for securing all theplates simultaneously and enabling the quick disengagement of theclamping means for the removal ci the printing plates, and it consistsessentially of the arrangement and construction of parts as hereinafterincre particularly explained.

Fig. 1 is a perspective view of a fragmentary portion of a press showingthe plate cylinder and impression cylinder and my device appliedthereto, the cylinder being intermediately broken away of its length.

Fig. 2 is a longitudinal sectional View through the plate cylinder andadjacent portions, the plate cylinder being broken away intermediatelyof its length.

Fig. 3 is an enlarged sectional View through the plate cylinder.

Fig. 4 is a similar view to Fig. 3 through the impression Cylinder.

Fig. 5 is a sectional view oi a fragmentary portion or" the platecylinder showing the parts in the initial attaching position.

Fig. 6 is a perspective detail of one of the wedging bars.

Fig. '7 is a fragmentary portion of the irnpression cylinder pad.

Fig. 8 is a sectional View through the bar 18.

ln the drawing lire characters of reference indicate corresponding partsin each figure.

1 and 2 indicate the side bearing standards of the machine in which theplate cylinder shaft 3 and impression cylinder shaft 4 are journalled inthe usual manner and provided With intermeshing gears 5 and 6. 7 and 8are respectively the plate cylinder and impression cylinder formedintegral with or secured to their respective shafts 3 and a. Thecylinders 7 and 8 are @if provided with longitudinal grooves 7X and 8X.9 represents the printing plate forming one printing element Which isthin sheet metal and is Wrapped around the cylinder 7, the ends 9X andbeing bent at right angles to the pad of the f plate and inserted ineach side oi the groove "IX as will hereinafter appear.

10 is the impression cylinder pad forming the other printing elementwhich is of sheet rubber and is Wrapped around the cylinder 8 so as tocontact peripherally With the exterior surface of the plate 9, the endsof the pad being inserted in the groove 8X and secured therein by meanswhich I will hereinafter describe.

l1 and 12 are collars turnably mounted upon the shaft 3 at each end ofthe cylinder 7 each provided, in its inner face or the face opposing theend of the cylinder, with an eccentric groove 11X having an opening 11formed in the eX- terior wall oi the groove for a purpose which willhereinafter appear. 1S and 14 are similar collars turnably mounted uponthe shaft 4 at each end of the impression cylinder 8.

The collars 11, 12, 13 and 14 are preferably provided with an exteriorknurled portion 15 so as to enable of the collar being manually grippedfor the purpose of turning and if desired such portion may be providedWith a series of holes for the insertion of a pin Wrench for aiding inturning the collars to their operative position.

The impression cylinder pad is provided adjacent one edge, with a seriesof orices 10X through Which, when such edge is inserted in the grooveSX, extend short pins 16X equal in length to the thickness of the pad10. By this means one end of the pad is attached in position, the freeportion of the pad being Wrapped around the cylinder 8 and the other orfree end then inserted in the groove 8X, a portion of the pad 17 beingon one side of the groove and a portion 1'1X on the opposite side.

It will be noted that the bar 18 is provided, near its inner edge, withshort spicular projections 18 and near its opposite edge with longerspicular projections 18, just long enough to ex- 10.5 tend through thepad and so as not to prevent the pad entering the groove 8X. When thebar is drawn edgewise into the groove, by means which I will hereinafterdescribe, the short pins 18X iirst engage the pad drawing it into theil.

groove to the bottom thereof, the projections 18 then engaging the padand passes through the same so as to have a tight hold thereon to drawthe pad into position tightly around the cylinder 8.

When the pad 10 is attached one end 9 of the plate 9 is inserted in thegroove 7X, the cylinder '7 is then revolved with the plate in contactwith the pad l0 thereby bending and wrapping such plate tightly aroundthe cylinder 7 until the opposite end is in position for insertion intothe groove.

In order to initially hold the portion 9X in the groove during thisoperation a bar 20 is inserted in the groove so as to bear against theportion 9X, being forced thereagainst by means of a leaf spring 21 whichis secured, at its outer end, in a recess 22 formed in the bar asclearly indicated in Fig. 5, the free end of the spring 21 bearingagainst the opposite wall of the groove. When the opposite end 9o of theplate is inserted within the groove a wedging bai1 23 is then forcedinto the groove between the plate portion 9 and the opposing face of thebar 20 thereby compressing the spring 21 into the recess 22 to allow thebar to assume the position shown in Figs. 1 and 3. As the bar is forcedinto this position, by means which I will hereinafter describe, sharpteeth or projections 23X formed by indenting the surface of the metalbar is indicated at 23o thereby forming a projection with a transversecutting edge which, when the bar is forced into position within thegroove, cuts into the metal forming the portion 9o of the plate anddraws such portion tightly into the groove and the plate into tightcontact with the exterior surf ace of the cylinder 7.

I will now describe the means by which the bars 18 and 23 are forcedinto their securing position. As this means is identical I will onlydescribe it in connection with the bar 23.

The bars 23 and 18 are provided at each end with the pin projections 24and 25 which, when the bar is initially placed in the groove 7X or 8X,pass through the entering notches or opening 11 formed in the wall ofthe eccentric groove 11X so as to enter such groove at each end of thecylinder 'l and 8.

The collars 15 and 16 or 13 and 14 are then turned, the eccentricity ofthe groove in each case forcing the pins 24 and 25 inward carrying thebars radially into position within the grooves '7X and 8X as abovedescribed. By this means it will be seen that both the plate and pad aresecured to a cylinder of very small diameter with the opposing ends ofthe plate or pad in very close proximity to each other so thatpractically none of the usual surface is Wasted thereby permitting ofthe use of a very small cylinder for the printing of small items such asletter heads enabling the interchange of a plate from job to job at acomparatively small cost. 'Ihe plate and pad are, of course, detached byturning the collars 15 and 16 or 13 and 14 in opposite directions tothat above'described so that the bars 23 and 18 are forced in theopposite or outward direction to free the ends of the plate or pad.

What I claim as my invention is:

1. In a press cylinder having a narrow deep longitudinal groove therein,the combination with a printing element having inturned end edges one ofwhich fits against one wall of said groove, a bar equal in width to thedistance between both inserted inturned element ends one side face ofwhich slidably bears against one inserted element end during the barsinsertion and engaging mea-ns between the other side face of the bar andthe other inturned element end adapted as the bar is inserted to drawthe uninserted element end to the inserted position, and means forforcing the bar edgewise into the groove.

2. In a press cylinder having a narrow deep longitudinal groove therein,the combination with a printing element having inturned end edges one ofwhich is anchored to one wall of said groove, a bar equal in width tothe distance between both inserted inturned element ends, one side faceof which slidably bears against one inserted element end during the barsinsertion, and teeth formed on the other side face adapted to engage andtear into the other inturned edge portion of the element as it is drawnthereby into the groove as the tension on the element approaches thestretching point of the element.

3. In a press cylinder having a narrow deep longitudinal groove havingparallel walls, of a printing element having inturned end edge portions,one of said inturned ends fitting against one wall of the groove, a barequal in Width to the distance' between both inserted inturned elementends one side face of which slidably bears against one inserted elementend during the bars insertion, and teeth formed on the other side faceof the bar equal in depth to the thickness of the element so that thecutting edges of the teeth reach the other side wall of the groove andadapted when engaged to tear into the other inturned edge portion of theelement as it is drawn thereby into the groove and as the tension of theelement aproaches the stretching point of the element.

WALTER HAROLD SMITH.

